Reversible manipulation of the magnetic state in SrRuO3 through electric-field controlled proton evolution

Abstract

Ionic substitution forms an essential pathway to manipulate the structural phase, carrier density and crystalline symmetry of materials via ion-electron-lattice coupling, leading to a rich spectrum of electronic states in strongly correlated systems. Using the ferromagnetic metal SrRuO 3 as a model system, we demonstrate an efficient and reversible control of both structural and electronic phase transformations through the electric-field controlled proton evolution with ionic liquid gating. The insertion of protons results in a large structural expansion and increased carrier density, leading to an exotic ferromagnetic to paramagnetic phase transition. Importantly, we reveal a novel protonated compound of HSrRuO 3 with paramagnetic metallic as ground state. We observe a topological Hall effect at the boundary of the phase transition due to the proton concentration gradient across the film-depth. We envision that electric-field controlled protonation opens up a pathway to explore novel electronic states and material functionalities in protonated material systems.

Recent Progress on Topological Structures in Ferroic Thin Films and Heterostructures

“…Although several independent studies reported indications of THE and associated skyrmions in ultrathin layers of ferromagnetic SrRuO 3 via transport measurements, [ 34,41,154,156,157,171–173 ] while these indications are questioned by other models very recently. [ 174–181 ] For instance, both Kan et al.…”

“…THE signal was also observed in other functional oxide thin films and heterostructures, as shown in Table 1. [ 34,155–157,166,167,169,172,177,182,183 ] For instance, the magnitude of ρ THE in the ferromagnet EuO thin films can reach up to 12 µΩ cm at 50 K, nearly two orders of magnitude larger than that in SrRuO 3 . [ 167 ] Furthermore, Vistoli et al.…”

Defects in complex oxide thin films for electronics and energy applications: challenges and opportunities

“…275 Similar reversible phase transformations mediated by hydrogen and oxygen ions was also observed in VO 2 , ZnO, WO 3 , SrRuO 3 , La 1Àx Sr x MnO 3 , La 0.7 Sr 0.3 MnO 3 /SrIrO 3 superlattice films, etc. 18,164,[276][277][278][279][280][281] Water was also used as a gating medium for achieving hydrogen doping. 282 The ionization of water to form H + and OH À occurs when a bias voltage over 1.23 V is applied between an electrode and TMOs in water.…”

Tailoring Dzyaloshinskii–Moriya interaction in a transition metal dichalcogenide by dual-intercalation

“…4b , when the gate voltage increases (shifts the Fermi energy towards the negative values), the strength of DMI becomes larger. Besides the gate-induced change of carrier density, the proton intercalation may locally form proton concentration gradient which can also lead to the SIS breaking and contribute DMI 34 . Specifically, the DMI at is about twice of the value at .…”